The fate of Saif al-Islam Gaddafi, the last remaining son of the late Libyan
leader, remained a mystery last night despite authoritative claims that he
had been captured and was being treated in hospital.

Saif al-Islam, often seen as his father's future successor due to his good links with the West, particularly Britain where he studied for a PhD in political democratisation, has proved the most elusive of all his offspringPhoto: REUTERS

He was said by Mohammed Alagy, the interim justice minister, to have been seized trying to escape from Sirte and to be in hospital in the city of Zlitan west of Misurata.

Press TV, the Iranian television station, even claimed he had lost an arm in the fighting, though it did not give a source for its information.

But other NTC officials, including Mohammed Shammam, the information minister, said they did not have a clear picture of where Saif al-Islam was.

According to another account, he was fleeing towards the Niger border in a convoy of vehicles to join his brother Saadi who has already taken refuge there.

Saif al-Islam, often seen as his father's future successor due to his good links with the West, particularly Britain where he studied for a PhD in political democratisation, has proved the most elusive of all his offspring.

He was reported captured in the fall of Tripoli, an arrest even confirmed by the International Criminal Court which has indicted him, but later turned up in person to deny the claim to journalists still in the Rixos Hotel in the city.

He was then reported to be in the city of Bani Walid, directing its defences. On one occasion, fighters there told The Daily Telegraph they had seen him fleeing south in a large convoy of vehicles, making claims of his later being in Sirte to the north, which was already surrounded, hard to believe.

Al-Arabiya, a Dubai-based television station, last night quoted a former rebel saying that his forces would allow Saif al-Islam to be filmed in hospital "after bandaging his wounds". But several hours later there was no sign of this or any other confirmation of his being under NTC control.

Meanwhile, Niger said it would lift travel restrictions on the scores of Gaddafi-era officials who fled to the country after the fall of Tripoli, a move likely to anger Libya's new rulers who will be seeking the extradition of many. The Niger government said it had no legal reason to hold them now that the war next door had finished.

It said that Saadi Gaddafi, who is subject to an Interpol "red notice" on a request by Libya for his extradition over alleged crimes connected to his role as head of the Libyan Football Federation, was an exception. He has been subject to a United Nation travel ban since early in the uprising.

"He's the target of a UN Security Council resolution travel ban," the foreign minister, Mohammed Bazoum, said. "He's in Niger, we're obliged to apply this resolution."

Of Col Gaddafi's other family members, his wife, Safiya, and three of his children, Mohammed, Hannibal and Aisha, fled to Algeria. Khamis, leader of the feared 32nd Brigade, died as he fled Tripoli in late March, while Mutassim, his father's national security adviser, also died after being captured during the fall of Sirte. Saif al-Arab, who was not involved in politics, died in a NATO bombing raid.